Self-locking screw



C. E. JOHNSON SELF LOCKING SCREW Filed March 18, 1935 Patented Apr. 7, 1936 UNITED STATES ATENT OFFICE 7 Claims.

This invention relates generally to self looking means and more particularly to such self locking of a valve tappet construction.

In my Patent No. 1,957,784, issued May 8, 1934,

a construction for maintaining two members in adjusted relationship is shown, and the instant invention contemplates an addition and improvement. In both the patent and in this application, the usual lock nut is eliminated whereby ease of adjustment and economy in manufacture is obtained.

In the present invention the two parts are quickly and easily adjusted relatively to one another and the threaded member is formed with its threads of the same diameter throughout. The associating of the two elements causes a distortion or bending of the threaded member and this bending .plus the resistance of the other element thereto causes a powerful locking action.

Other advantages will become apparent as the description proceeds.

In the drawing:

Fig. 1 is a side view of a tappetembodying my invention.

Fig. 2 is a vertical sectional view taken through Fig. 1.

Fig. 3 is a vertical sectional view taken at right angles to Fig. 2.

Fig. 4 is a sectional View upon the line 4-4 of Fig. 3.

Fig. 5 is a fragmentary vertical cross sectional view of a different form or embodiment of the invention.

Fig. 6 is a sectional view taken upon the line of B6 of Fig. 5.

Fig. 7 is a fragmentary vertical sectional view of another embodiment of the invention.

Fig. 8 is a side view of the structure shown in Fig. '7.

Fig. 9 is a sectional view taken upon the line 9-9 of Fig. 8.

Like reference characters refer to like parts throughout the several views of the drawing.

Referring to Figs. 1-4, inclusive, numeral II] indicates the body portion of a valve tappet which has a head II partly separated therefrom by a slot I2 which extends approximately half way through the body as clearly shown in Fig. 4. The head I I is also vertically slotted as indicated at I3, whereby it may expand, and flats I4 are formed to receive the adjusting wrench.

As shown in Figs. 2 and 3, the body I0 and its head II are interiorly recessed and threaded as indicated at I5. This thread is of constant diameter throughout.

A screw member 20, having a head 2|, is provided with threads 22 as clearly shown in Figs. 2 and 3 of the drawing. These threads are oversize threads as regards the threaded hole I5 and are of a constant diameter throughout. The lower end of the screw member 20 has a longitudinal opening 23 extending upwardly from its lower end for a distance and a slot 24 is cut in one side from said opening 23 to the outside of the member 23.

Numeral 25 (see Fig. 3) indicates the axis of the threads I5 while numeral 26 illustrates the axis of the threaded member 20.

The operation of this construction is easily understood. The members are threaded together as shown and the lower end of the member 20 compresses somewhat as the members are threaded together. This is permitted by the opening 23 and the slot 24. The lower portion of the threaded stem 20 easily passes through the head member II inasmuch as both of these members are compressible but when the parts are located as shown in Figs. 2 and 3, the oversize threads of the stem expand the head portion II and this expansion occurs eccentrically and thus causes the threaded stem 23 to bend to the left as shown in Fig. 3. At the same time the lower part of the threaded member 20 is compressed when it is screwed into the part of the body portion 20 below the head II, and a very secure locking of the body and member 20 is obtained. However, adjustment may be made therebetween by means of-wrenches.

Referring now to Figs. 5 and 6, numeral 33 indicates the body member, threaded at 3| and. having flats 32. The upper member 35, having a head 36, is threaded to a constant diameter at 31 and has a longitudinal opening 38 extending from its, lower end nearly to the head 36 and, preferably, to one side of the central axis of member 35. A slot 39 extends radially from the hole or recess 38 to the outside of the member 35. As clearly shown in Fig. 6, the hole 38 is eccentrically positioned and this location gives an eccentric cross sectional shape to the stem 35 whereby compression thereof, due to the threads 31 being oversize relative to the threads 3|, will cause the contraction to be in a true circle.

The operation of this modification is to simply screw the two elements together as shown in Fig. 5 and the outward pressure of the contractible stem 35 securely holds the parts in position.

Referring now to the modification shown in Figs. 7, 8 and 9, numeral 40 indicates a body member which is threaded at 4| to receive a suitable screw 50 with oversize threads thereon. The body member 40 has a slot 42 extending downwardly from its upper end and a diametrically opposed slot 43 located therebelow as clearly shown in Figs. 7 and 8 of the drawing.

In the operation of this modification, the screw element 50 is threaded downwardly and, being oversize, causes eccentric expansion of the body member 40 and this in turn, causes a gripping on of the element 50. This gripping causes a powerful locking effect to be exerted between these two members.

The invention has proven exceptionally practical and capable of withstanding the service to which it is subjected in practice. The invention is defined in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. A device of the class described comprising, a body having a screw threaded hole therein, a member having a screw threaded stem for entering said hole, said stem being slightly oversize for the hole, and said screw threaded hole and the threaded portion of said stem having uniform diameters throughout their lengths, one of said elements being cut away whereby a certain amount of yieldableness is obtained for permitting relative diametric change of the said element when the elements are threaded together, said change being resisted by the said body, whereby a tight binding engagement of the body and stem is obtained.

2. In combination, an elongated body having a centrally located interiorly threaded hole extending from its upper end downwardly for a distance, said screw threaded hole being of a uniform diameter, an oversized screw threaded member screwed into the body, the threaded portion of said member being likewise of uniform diameter throughout its length, said screw being cut away to permit a contraction of the screw so that the screw may enter said hole and be adjusted lengthwise thereof but resist turning movement, as and for the purposes specified.

3. In combination, a body having an elongated axial threaded hole therein extending from its upper end downwardly for a distance, said body having a slot in one side extending downwardly from its upper end part of the length of the hole, and a second slot in the opposite side of the body, the upper end of which is above the lower end of the first mentioned slot and below the upper end thereof, and the lower end of which extends below the lower end of said first slot, and an oversized screw of constant diameter threaded into said body.

4. In a device of the class described, an elongated substantially cylindrical body having an axial screw threaded hole of uniform diameter extending from its upper end downwardly a distance into the body, said body being slotted to permit a slight diametric enlargement thereof, a screw threaded member having a diameter slightly larger than the diameter of said hole screwed into said body and serving to diametrically expand the body, the expansion of the body being resisted by said body whereby a tight binding engagement of the body against the screw threaded member is obtained.

5. In combination, an elongated body having a screw threaded hole of uniform diameter disposed axially therein and extending from its upper end downwardly for a distance, and a screw threaded member having a uniform diameter slightly larger than the diameter of said hole in the body threaded into said body, said screw threaded member having a longitudinal opening therein from its lower end upwardly and a slot extending substantially the length of said opening and outwardly therefrom to the outer side of the screw threaded member, whereby the screw threaded member may be diametrically contracted when screwed into the body.

6. In combination, an elongated body having an axially disposed interiorly threaded hole of uniform diameter extending from its upper end downwardly a distance into said body, said body being longitudinally slotted at one side from its upper end downwardly substantially one-half the length of said hole, and said body also having a slot in its opposite side of substantially the same length as the first slot but with its upper end between the upper and lower ends of the first slot and with its lower end below the lower end of the first slot, and an exteriorly screw threaded member of uniform diameter adjustably screwed into the body, the exterior diameter of said screw threaded member being slightly larger than the interior diameter of the screw threaded hole.

'7. A device as set forth in claim 1 in which the cut away part of the said element extends only a predetermined axial distance whereby an increased binding or frictional effect is obtained at the desired degree of axial engagement between the said body and member.

CHARLES E. JOHNSON. 

